Delivery vs workflow are different problems
Most comparisons mix delivery infrastructure (Postmark, SES, Resend) with workflow and template management tools (Customer.io, else.events). They solve different problems.
Honest evaluation guide
How to choose the right transactional email service for your SaaS
There is no single best transactional email service — the right choice depends on whether you need delivery infrastructure, a workflow and template layer, or both. This guide helps you decide.
Why choosing a transactional email service is harder than it looks
SaaS product emails need more than a sending API
Password resets and billing alerts are simple. But routing by plan, locale and tenant, managing templates outside your codebase and tracing which event triggered each email — these need a workflow layer.
Pricing models differ significantly
Some tools charge per contact, others per email sent, others by feature tier. For SaaS teams, email volume grows with product usage — not necessarily with contact list size.
Lock-in is a long-term risk
Provider-specific templates, SDKs and APIs make switching expensive. Evaluating flexibility early avoids costly rewrites.
The two layers of a SaaS email stack
Most SaaS teams need two things: a delivery layer and a workflow layer. Understanding which you need — and how they interact — is the key decision.
Layer 1: Delivery infrastructure
Postmark, Resend, SendGrid, Mailgun, Amazon SES — these send emails reliably. They handle DKIM, bounces, deliverability and at-scale volume.
Layer 2: Workflow and template management
This is where event-driven routing, rule-based template selection, locale support, versioning and non-technical template editing live. else.events is in this category.
Hybrid tools
Customer.io, Brevo and Loops combine both layers with marketing automation. Right for some teams, overkill for others.
The SaaS-typical stack
Postmark or Resend for delivery + else.events for workflow and templates. Clean separation, no marketing overhead, provider-agnostic by design.
Comparison: transactional email services for SaaS
| Criterion | Postmark | Resend | SendGrid | Amazon SES | else.events |
|---|---|---|---|---|---|
| Delivery infrastructure | ✓ (best-in-class) | ✓ (developer-first) | ✓ (broad) | ✓ (low cost) | ✗ (uses your provider) |
| Event-driven routing | ✗ | ✗ | ✗ | ✗ | ✓ |
| Rule-based template selection | ✗ | ✗ | ✗ | ✗ | ✓ |
| Template management UI | Basic | ✗ | Dynamic Templates | Basic | ✓ (versioned + locales) |
| Locale support | Manual | Manual | Manual | Manual | ✓ |
| Multi-tenant support | ✗ | ✗ | Limited | ✗ | ✓ |
| Domain event logs | ✗ | ✗ | ✗ | ✗ | ✓ |
| Pricing model | Per email | Per email | Volume tiers | Per email (very low) | Per email |
| Provider lock-in | Medium | Medium | High | High | None |
This comparison focuses on SaaS product email use cases. All tools have capabilities not listed here. else.events is not a delivery provider — it works with Postmark, Resend, SMTP and more.
How to choose: a decision framework
- 01
Start with your primary need
Do you need reliable delivery at scale? → Postmark, Resend or SES. Do you need event-driven routing, rule-based templates and template management? → else.events. Both? → Use them together.
- 02
Evaluate your team
Developer-first teams building SaaS backends benefit most from an event API model. Marketing-heavy teams may prefer platforms like Loops or Customer.io that include lifecycle automation.
- 03
Consider your growth trajectory
If you plan to add locales, multi-tenancy or non-technical template editing as you scale, plan for those now. Retrofitting a delivery API with a workflow layer is much harder than building it in from the start.
- 04
Check pricing against your usage model
Contact-count pricing (Customer.io, Brevo) is unpredictable for SaaS teams. Per-email pricing (Postmark, Resend, else.events) is more predictable when email volume grows with product usage.
- 05
Evaluate provider flexibility
If you want to switch delivery providers later — or use different providers for different workloads — choose a workflow layer that is provider-agnostic from day one.
When else.events is the right fit
You want event-driven email workflows
Your app fires domain events — invoice.payment_failed, user.signed_up, trial.ending_soon — and you want the email layer to handle routing, template selection and delivery.
You want templates outside your codebase
Non-technical team members should be able to update email copy without a deploy cycle.
You are building multi-tenant SaaS
Different templates or brand variables per tenant, without multiplying application logic.
You want to stay provider-agnostic
Use Postmark today, switch to Resend tomorrow — without changing a line of application code.
Frequently asked questions
- What is the best transactional email service for SaaS in 2025?
- There is no single answer. For pure delivery, Postmark and Resend are strong developer-first options. For event-driven workflows and template management, else.events adds the layer that delivery APIs lack. Many SaaS teams use both: a delivery provider + else.events for workflow and templates.
- Should I use Postmark or else.events?
- Postmark excels at reliable delivery. else.events adds event-driven routing, rule-based template selection and template management on top. They are not alternatives — they complement each other. Use both.
- Is Amazon SES good for SaaS product emails?
- SES is cost-effective at scale but requires significant infrastructure work — DKIM, bounce handling, complaint management, sandbox lifting. SaaS teams often start with SES and add a workflow layer like else.events when template management and event routing become a bottleneck.
- What is the difference between transactional email and marketing email?
- Transactional emails are triggered by user actions or domain events — password resets, billing alerts, invitations. Marketing emails target contact lists — newsletters, campaigns, drip sequences. They require different tools. else.events is built for transactional and product emails, not for marketing campaigns.
- How important is provider flexibility?
- Very important for long-term SaaS teams. Provider deliverability, pricing and support change over time. Building your application against else.events — which is provider-agnostic — means you can switch providers without touching application code.
Build your SaaS email stack on a solid foundation
Event routing, rule-based template selection, template management and delivery logs — works with Postmark, Resend, SMTP and more.
- Free during public beta
- Provider-agnostic by design
- No contact database required